1. Technical Field
The present disclosure generally relates to a fray tester for sutures. In particular, the disclosure relates to a test apparatus and related methods for evaluating fray resistance or break-down performance of a surgical suture when rubbing against itself.
2. Background of the Related Art
Sutures are often used in surgical procedures for holding cut tissue surfaces in apposition for a period of time sufficient for healing. Non-absorbable sutures, e.g. sutures made from non-bioabsorbable materials such as polyolefins, nylon, cotton, and the like, are generally removed after a period of time. Absorbable sutures, e.g. those fabricated from bioabsorbable materials such polymers of lactide and glycolide, collagen, and the like, are gradually degraded and absorbed by the body, and do not require subsequent removal.
A suture having a good degree of flexibility and pliability can conform closely to body tissue without undue pressure. Good flexibility and pliability enhance the degree to which a suture can be tied down, knotted and securely placed in a desired position. Various attempts have been made to modify and optimize the physical characteristics of gut sutures. For example, various suture coatings and tubing fluids-have been developed to achieve or enhance flexibility and pliability, and also to improve the handling characteristics of sutures, such as fray resistance or run-down performance.
In addition to the research efforts on suture materials, coatings and tubing fluids, several testing techniques have been adopted for evaluating such handling characteristics of sutures.
An example of a fray resistance test is described in U.S. Pat. No. 5,584,858. Such fray tester utilizes a static suture wound around rollers, and a dynamic suture wrapped twice at a point around the static suture with a weight attached at one end of the dynamic suture, the dynamic suture being subject to rubbing cycle against the static suture until the sutures break to stop the test.
The present disclosure is directed to a fray tester for evaluating fray resistance characteristics of surgical sutures. Simulating real surgical operations where the surgeon repeatedly knots the suture, the fray tester is adapted to provide repeated rubbing action at a wrapped portion of the suture while counting the number of such rubbing cycles until the suture seizes or breaks down.
The fray tester comprises first and second pulleys rotatably adapted in a spaced relation to each other, a tensioning weight, and a reciprocating driver. In operation, a suture having a first end portion, a second end portion and an intermediate portion is mounted in the tester with the second end portion being subject to the tensioning weight, the intermediate portion mounted around the first and second pulleys and defining a wrapped portion, the first end portion being connected to the reciprocating driver which causes the intermediate portion of the suture to rub against itself at the wrapped portion.
In a preferred embodiment, the reciprocating driver is a rotating wheel connected to a motor for providing the reciprocating movement to the suture to be tested. The tester may further include a revolution counter for counting and displaying the number of cycles at the time the suture breaks, seizes or reaches some predetermined state of degradation.